PROJECT SUMMARY/ABSTRACT Occupational noise is a widespread risk factor, linking it strongly to critical health hazards, such as hearing loss, psychiatric disorders, increased blood pressure, and harmful biochemical, immune system, and birth-weight effects. Hearing loss results in social isolation, lost productivity, increased injuries, and expenses for workers' compensation and hearing aids. High levels of occupational noise remain a problem in all regions of the world [1]. In the United States, every year more than 30 million workers are exposed to hazardous noise. Noise-related hearing loss has been listed as one of the most prevalent occupational health concerns in the United States for more than 25 years [2]. Thousands of workers every year suffer from preventable hearing loss due to high workplace noise levels. Since 2004, the Bureau of Labor Statistics (BLS) has reported that nearly 125,000 workers have suffered significant, permanent hearing loss. In 2009 alone, BLS reported more than 21,000 hearing loss cases [2]. The National Institute for Occupational Safety and Health (NIOSH) is committed to ensuring a safe and healthful working environment to all employees and others involved in or affected by its operation. NIOSH is interested in developing personal noise-exposure monitoring system that can immediately alert user when a sound hazard occurs. Current noise measurement procedures and devices, such as noise alert badges and personal sound exposure meters (noise dosimeters), cannot effectively alert the user when a noise hazard occurs because they typically do not have a noise hazard indicator located within the user's visual field or do not provide any indicator. To address this problem, Physical Optics Corporation (POC) proposes to develop a novel Light-Alarming personal Noise Dosimeter (LAND) system that integrates a wearable noise dosimeter with an innovative light alarming device. Innovations in light alarming device design allow-without any modification to existing personal protective equipment-placing the color-coded lights in worker's field of view to provide real-time warning of dangerous noise condition and exceeded noise dose. Recorded noise history can be transferred to personal computers (PC) for later analysis. In Phase I POC will develop a LAND system architecture that provides accurate noise level and noise exposure measurement and effective visual alerts of sound hazard. POC plans to demonstrate the feasibility of the LAND concept by demonstrating a system prototype's ability to accurately measure and effectively alert users of hazardous noise level and exceeded exposure to noise; automatically collect, process, and store measured data, and transfer this data to a PC. Successful demonstration in Phase I of a proof-of-concept system prototype will lead to a commercially useful prototype in Phase II. A low cost LAND provides both noise level/exposure monitoring and real-time user alerting, thus it can be adopted widely to deal with this pervasive problem, preventing hearing loss and other environmental noise-related afflictions while reducing the cost of conducting noise surveys and hearing conservation programs.